1. Field of the Invention
The present invention relates to an image processing apparatus, an image processing method, and a computer program, and in particular, relates to an image processing apparatus, an image processing method, and a computer program for improving image blurring generated when dynamic images are displayed in a hold-type display device such as a liquid crystal display device.
2. Description of the Related Art
An issue of dynamic images being blurred arises when they are displayed in a hold-type display device such as a liquid crystal display device. Dynamic image blurring in a hold-type display device such as a liquid crystal display device is caused by a hold effect in which pixels displaying an image hold display content also in a non-selection period. In a liquid crystal display device, dynamic image blurring is also caused by the fact that a liquid crystal response is incapable of sufficiently following a driving voltage depending on a level change pattern of the voltage (driving voltage) input to pixels due to slowness of the response speed of liquid crystal.
As a method of preventing dynamic image blurring by the hold effect, a method of performing time division driving as false impulse driving as if to artificially provide an impulse display is known. Time division driving as false impulse driving is a driving method for providing a display in such a way that brightness in accordance with an input image is perceived by dividing one frame period for displaying into a plurality of sub-frames, displaying each sub-frame with different display luminance, and integrating the display luminance thereof with time.
That is, a display near an impulse-type display can artificially be provided also in a hold-type display device by performing time division driving and providing a low-luminance display (a display near a black display) to at least one sub-frame among the plurality of divided sub-frames, producing an effect of preventing dynamic image blurring.
Also as a method of preventing dynamic image blurring caused by slowness of the response speed of liquid crystal, a method of correcting a liquid crystal response called an overdrive is known. The overdrive is a method by which when the signal level of pixels driving a liquid crystal changes between frames, a high signal level or low signal level is temporarily applied in accordance with change in level to accelerate movement of the liquid crystal so that a display in accordance with an input image can be provided. By applying the signal in this manner, an effect of preventing dynamic image blurring is produced.
Since time division driving as false impulse driving and the overdrive are different in their intended factors to solve, they can be used in combination to improve dynamic image blurring of a liquid crystal display device and the like. And a method is known by which, when they are combined, the overdrive is performed after time division driving as false impulse driving.